| Factor |
Category |
Definition |
| Characterising species |
|
A list of those species considered to best characterise the
biotope together with associated information on their frequency of occurrence, degree of
faithfulness and the typical abundance at which they occur. |
| % Frequency of occurrence |
|
The species listed include those which are constants
(i.e. they occur in >60% of the records for the type) plus those which occur in less
than 60% of the records but which are highly faithful or moderately faithful.
The symbols represent percentage occurrence in the samples as follows: |
| |
· · · · · |
Occurs in 81-100% of the records for the type |
| |
· · · · |
Occurs in 61-80% of the records for the type |
| |
· · · |
Occurs in 41-60% of the records for the type |
| |
· · |
Occurs in 21-40% of the records for the type |
| |
· |
Occurs in 1-20% of the records for the type |
| Degree of faithfulness |
|
This is indicated by the following guidelines, based on the
relevant major habitat and the appropriate level in the classification (i.e. Ascophyllum
nodosum may be considered moderately faithful at the biotope level, but highly
faithful at the biotope complex level): |
| |
· · · Highly faithful |
species restricted to this or very closely related types |
| |
· · Moderately faithful |
species found in this and other related types in the relevant
major habitat |
| |
· Poorly faithful |
species found very widely in the relevant major habitat |
| Typical abundances |
|
These are given according to the MNCR abundance scales (see
Appendix) in Connor et al. (1997a, b) which are the scales used for all MNCR and
BioMar field recording for in situ surveys. Sediment infaunal sampling usually
yields counts of individuals per sample; these have been converted to the MNCR abundance
scale for compatibility of data presentation here. The abundance given is a mean abundance
derived from the records assigned to the biotope. |
